In agricultural seeding operations agricultural materials, such as seed and fertilizer, are deposited in furrows that are opened in the soil by a furrow opener. The furrow openers are attached to an implement frame and pulled along a field.
Agricultural materials are carried from a storage tank or the like by one or more tubes that have output ends attached to the furrow opener. The agricultural materials pass from the output end of the tube into a seed boot or the like attached to the furrow opener that directs the material into the furrow. For liquid fertilizer, the output end of the tube may simply be oriented such that the liquid drops into the furrow. Double shoot furrow openers are also available where two furrows are formed and different agricultural materials are directed into each furrow.
Although such furrow openers are known in a wide variety of configurations, one common configuration includes a rotating disc. The disc is typically rotatably attached, in a generally upright orientation, to an arm which in turn is pivotally attached to the frame about a substantially horizontal axis so as to allow the disc to move up and down. The furrow opener apparatus will include some means, such as a spring, hydraulic cylinder, or the like, to bias the arm downward such that the lower edge of the disc engages the ground to create a furrow.
The rotational axis of the disc is typically oriented at an angle to the direction of travel such that when the disc is pushed down into the soil, soil is moved laterally along a leading face of the disc, and a groove or furrow is thus created adjacent to the trailing face of the disc. The output end of the tube is attached to the furrow opener adjacent to the trailing face of the disc and directs agricultural materials into the furrow just behind the trailing face.
Soil and debris sometimes clings to the trailing face of the disc and can prevent the agricultural materials from falling into the furrow, or jam in the output end plugging the boot or tube. The agricultural material generally falls down adjacent to the trailing face, and so such soil and debris blocks its path, with the result that the agricultural material falls on the ground adjacent to the furrow, or only part way into the furrow. Ideally the agricultural material falls right to the bottom of the furrow, and it is the objective of furrow opener design to have the disc and material outlet oriented relative to each other to achieve that end.
To clean the soil and debris from the trailing face of the disc a scraper is typically provided with a blade parallel to, and closely adjacent to or touching, the trailing face. Often the scraper is biased against the trailing face. The scraper is located generally against a lower portion of the trailing face of the disc. The blade of the scraper is located generally across the trailing face so that a substantial portion of the face from near the outer edge of the disc towards the center thereof is scraped clean.
The scraper can also serve to prevent soil from falling back into the furrow before the agricultural material is deposited. Typically the scraper is oriented at an angle outward from the blade, and the agricultural material output is located behind the scraper such that the path of the agricultural material into the furrow is protected from soil and debris that is disturbed by the disc or scraper, and such that the agricultural material is confined adjacent to the trailing face, and conveniently between the scraper and the trailing face of the disc, and so falls into the furrow. For satisfactory operation, the disc, tube and scraper must be oriented in a cooperating relationship to each other so that the agricultural material falls into the furrow.
Examples of furrow openers incorporating scrapers and means for delivering agricultural materials to a furrow are disclosed in U.S. Pat. No. 6,024,179 to Bourgault, U.S. Pat. No. 6,260,632 to Bourgault et al., and U.S. Pat. No. 6,237,696 to Mayerle.
As the disc is used, it wears down and its diameter becomes smaller. The scraper does not typically wear in the same way, with the result that, as the disc becomes smaller, the scraper extends beyond the edge of the disc such that a portion of the scraper engages the soil instead of the trailing face of the disc. The scraper no longer engages the trailing face of the disc properly because of interference from the soil. Since it is desirable to scrape the trailing face fairly close to the disc edge, the disc can only wear a fairly small amount before the scraper extends beyond the disc edge and proper operation of the scraper is inhibited. The disc must then be replaced, requiring considerable expense and labor.